A compression-resistant composite shielded cable

Abstract

The present application relates to the technical field of cable, more particularly, it relates to a kind of anti-pressure composite shielded cable.Anti-pressure composite shielded cable, from inside to outside, includes the following parts: core, shielding inner layer, shielding outer layer, sheath layer, core includes conductor and the insulating layer of being arranged in the conductor outside, conductor is tinned copper stranded wire, shielding outer layer is woven from tinned copper wire;Wherein, the raw material of shielding inner layer is semiconductive shielding material, the composite conductive filler in semiconductive shielding material can enhance charge transport efficiency, reduce the volume resistivity of semiconductor shielding material, improve the conductive capacity of semiconductor shielding material;The raw material of sheath layer is pressure-resistant sheath material, the pressure-resistant sheath filler in pressure-resistant sheath material can more effectively transmit stress through good dispersion and interface bonding, reduce stress concentration, thereby improve the tensile and compression resistance of pressure-resistant sheath material.

Description

Technical Field

[0001] This invention relates to the field of cable technology, and more specifically, to a pressure-resistant composite shielded cable. Background Technology

[0002] Shielded cables are special cables with an added shielding layer outside the cable's insulation layer. Their core function is to isolate the signals and power transmitted inside the cable from the external electromagnetic environment, while also preventing the electromagnetic fields generated by the cable itself from radiating outwards. This reduces electromagnetic interference (EMI) and radio frequency interference (RFI), ensuring the stability of signal transmission and the safety of power transmission. In scenarios such as underground mining, tunnel construction, and heavy equipment towing, cables not only need stable signal shielding capabilities to resist external electromagnetic interference and ensure the integrity of transmitted signals and the safety of power delivery, but they also need to withstand long-term mechanical stresses such as compression and impact. Therefore, compressive strength and shielding performance are key indicators for evaluating the quality of such cable products.

[0003] In existing technologies, the shielding structure of shielded cables mostly employs a single metal wire braided layer or a semi-conductive shielding layer. Among these, metal wire braided shielding layers (such as tin-plated copper wire braided layers) are widely used in various cables requiring electromagnetic interference resistance due to their excellent conductive shielding performance. They form a closed shielding loop through the metal braid, effectively blocking the intrusion of external electromagnetic signals and suppressing the leakage of signals from within the cable. Semi-conductive shielding layers are mainly prepared by adding conductive fillers to a polymer matrix. Their function is to uniformly distribute the electric field within the cable and reduce the damage to the cable insulation layer caused by localized electric field concentration. Traditional semi-conductive shielding layers often use conductive carbon black-filled polymer systems, relying on the contact between conductive carbon black particles to form conductive pathways. However, conductive carbon black has poor dispersion in the polymer matrix and is prone to agglomeration, making it impossible to form continuous and stable conductive pathways within the shielding material. This not only leads to higher volume resistivity, affecting the uniform distribution of the electric field, but also causes fluctuations in shielding performance.

[0004] To improve the compressive strength of shielded cables, existing technologies typically add rigid fillers (such as calcium carbonate, talc, and wollastonite) to the sheath material to enhance hardness. However, these fillers have poor dispersion in rubber or plastic matrices, and when subjected to external pressure, stress tends to concentrate around the aggregates, leading to sheath cracking and ultimately reducing the cable's compressive strength reliability. Furthermore, the inorganic fillers used in existing technologies are mostly granular, which have limited ability to impede polymer chain slippage, failing to effectively improve the material's tensile strength and resistance to deformation, and thus making it difficult to meet the high compressive strength requirements of cables under complex operating conditions. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a pressure-resistant composite shielded cable.

[0006] A pressure-resistant composite shielded cable includes the following parts from the inside out: The product consists of a conductor, an inner shielding layer, an outer shielding layer, and a sheath layer. The conductor includes a conductor and an insulating layer disposed on the outside of the conductor. The conductor is tin-plated copper stranded wire. The outer shielding layer is woven from tin-plated copper wire; The inner shielding layer is made of semi-conductive shielding material, and the raw materials for preparing the semi-conductive shielding material include: 60-70 parts by weight of matrix resin, 10-18 parts by weight of composite conductive filler, 1-2 parts by weight of dispersant, 0.5-1.2 parts by weight of antioxidant, 1.8-2.4 parts by weight of crosslinking agent and 0.3-2.1 parts by weight of lubricant; The raw materials for preparing the composite conductive filler include: 9-15 parts by weight of conductive carbon black, 200-400 parts by weight of anhydrous chloroform, 4-7 parts by weight of thiophene monomer and 8-12 parts by weight of anhydrous ferric chloride. The raw material for the sheath layer is a pressure-resistant sheath material, and the raw materials for preparing the pressure-resistant sheath material include: 60-80 parts by weight of chloroprene rubber, 12-24 parts by weight of compression sheath filler, 0.5-1.6 parts by weight of antioxidant, 0.8-4 parts by weight of plasticizer and 1-5 parts by weight of vulcanizing agent; The raw materials for the pressure-resistant sheath packing include: Halloysite nanotubes supported on calcium carbonate and sodium dodecyl sulfate solution were prepared. The solid-liquid mass ratio of the halloysite nanotubes supported on calcium carbonate to the sodium dodecyl sulfate solution was 1:(16-20). The sodium dodecyl sulfate solution had a sodium dodecyl sulfate mass fraction of 1-4%. The halloysite nanotubes supported on calcium carbonate were halloysite nanotubes with calcium carbonate deposited on their surface.

[0007] Preferably, the insulating layer is made of one of cross-linked polyethylene, ethylene propylene rubber, or thermoplastic vulcanized rubber, and the wire core has at least one strand.

[0008] Preferably, the matrix resin is a compound of ethylene-vinyl acetate copolymer and low-density polyethylene in a mass ratio of (2-3):1.

[0009] Preferably, the preparation steps include the following: S1: Preparation of composite conductive filler: Conductive carbon black is dispersed in anhydrous chloroform to obtain conductive carbon black dispersion. Thiophene monomer and anhydrous ferric chloride are added to the conductive carbon black dispersion, and the mixture is stirred to react. After the reaction is completed, the filter residue is collected by filtration. The filter residue is washed and dried to obtain composite conductive filler. S2: Preparation of semiconductive shielding material: Mixing, extruding and granulating the raw materials required for preparing semiconductive shielding material to obtain semiconductor shielding material; S3: Preparation of halloysite nanotubes supported on calcium carbonate: Halloysite nanotubes were dispersed in anhydrous ethanol to form a halloysite nanotube suspension. Under nitrogen protection, 3-aminopropyltriethoxysilane was slowly added dropwise to the halloysite nanotube suspension and stirred to obtain modified halloysite nanotubes. The modified halloysite nanotubes were added to an aqueous solution containing calcium chloride and urea and slowly heated to allow the urea to slowly hydrolyze, continuously generating carbonate ions, which promoted the deposition of calcium carbonate. Subsequently, the solid product was collected by vacuum filtration, washed and dried to obtain calcium carbonate supported halloysite nanotubes. S4: Preparation of the compression-resistant sheath filler: Sodium dodecyl sulfate was dissolved in deionized water to prepare a sodium dodecyl sulfate solution. Calcium carbonate-supported halloysite nanotubes were mixed with the sodium dodecyl sulfate solution and heated and stirred for a period of time. Subsequently, the mixture was cooled to room temperature and then subjected to vacuum filtration, washing, and drying to obtain the compression-resistant sheath filler. S5: Preparation of the pressure-resistant sheath material: The raw materials required for the preparation of the pressure-resistant sheath material are mixed, extruded, and granulated to obtain the pressure-resistant sheath material; S6: The processing and preparation of the pressure-resistant composite shielded cable involves extruding semiconductor shielding material onto the surface of the core to form an inner shielding layer. On the outside of the inner shielding layer, tin-plated copper wire is braided using a high-speed braiding machine to form an outer shielding layer. Finally, a layer of pressure-resistant sheathing material is extruded onto the outer shielding layer to form a sheathing layer, thus obtaining the pressure-resistant composite shielded cable.

[0010] Preferably, the preparation of the composite conductive filler in step S1 specifically includes the following steps: S1.1: Add 9-15 parts by weight of conductive carbon black to 200-400 parts by weight of anhydrous chloroform and ultrasonically disperse at 20-26°C for 1-3 hours to obtain a conductive carbon black dispersion. S1.2: Add 4-7 parts by weight of thiophene monomer to the conductive carbon black dispersion obtained in step S1.1, stir for 1-3 hours, then add 8-12 parts by weight of anhydrous ferric chloride, stir at 18-24°C for 8-12 hours, filter after the reaction is complete, and wash and dry the filter residue to obtain the composite conductive filler.

[0011] Preferably, step S3, the preparation of calcium carbonate-supported halloysite nanotubes, specifically includes the following steps: S3.1: Place halloysite nanotubes in a vacuum drying oven and dry at 70-80℃ for 3-5 hours. Take 8-16 parts by weight of the dried halloysite nanotubes and add them to 100-150 parts by weight of anhydrous ethanol. Disperse by ultrasonication for 10-15 minutes to form a halloysite nanotube suspension. S3.2: Under nitrogen protection, 5-10 parts by weight of 3-aminopropyltriethoxysilane were slowly added dropwise to the halloysite nanotube suspension obtained in step S3.1, with the dropping rate controlled at 0.5-1 mL / s. The mixture was stirred for 30-40 min, heated to 80-94 °C, and stirred for 2-5 h. After the reaction was completed, the mixture was cooled to room temperature, and the solid product A was collected by vacuum filtration. After washing and drying, the modified halloysite nanotubes were obtained. S3.3: Take modified halloysite nanotubes and add them to an aqueous solution containing calcium chloride and urea at a solid-liquid mass ratio of (1-3):(30-80). Disperse the solution by ultrasonication at room temperature for 20-40 min to obtain a dispersion. Heat the dispersion slowly to 60-66℃ at a heating rate of 1-3℃ / min to allow the urea to hydrolyze slowly. After stirring continuously for 2-4 h, collect the solid product B by vacuum filtration. After washing and drying, obtain calcium carbonate supported halloysite nanotubes.

[0012] Preferably, the molar ratio of urea to calcium chloride in the aqueous solution containing calcium chloride and urea is 3:1.

[0013] Preferably, the preparation of the compression-resistant sheath filler in step S4 specifically includes the following steps: S4.1: Dissolve sodium dodecyl sulfate in deionized water to prepare a sodium dodecyl sulfate solution with a mass fraction of 1-4%; S4.2: Mix calcium carbonate-supported halloysite nanotubes with sodium dodecyl sulfate solution from step S4.1 at a solid-liquid mass ratio of 1:(16-20), ultrasonically disperse for 10-30 min, stir at 50-70℃ for 1-3 h, cool to room temperature, and obtain pressure-resistant sheath filler by vacuum filtration, washing and drying.

[0014] Preferably, the dispersant is at least one of polyethylene wax and ethylene bis-stearamide; the antioxidant is at least one of antioxidant 1010, antioxidant 1076, antioxidant TPP, and antioxidant 168; the crosslinking agent is triallyl isocyanurate or dicumyl peroxide; and the lubricant is at least one of microcrystalline wax, silicone oil, and zinc stearate.

[0015] Preferably, the plasticizer is at least one of dioctyl phthalate, dibutyl phthalate, and diisononyl phthalate; and the vulcanizing agent is at least one of tert-butyl perbenzoate, dicumyl peroxide, and tert-butyl cumyl peroxide.

[0016] Compared with the prior art, the present invention has at least the following advantages: 1. In this invention, conductive carbon black is ultrasonically dispersed in chloroform to form a stable dispersion. The conjugated structure on the surface of the conductive carbon black can serve as adsorption sites for thiophene monomers, allowing the thiophene monomers to be adsorbed onto the surface and pores of the conductive carbon black particles through van der Waals forces and π-π conjugation. Anhydrous ferric chloride is used as an oxidant to initiate oxidative coupling polymerization of the thiophene monomers on and around the conductive carbon black surface, forming polythiophene molecular chains. The conjugated π bonds of polythiophene are further combined with the conjugated structure of the conductive carbon black through π-π conjugation. At the same time, the polythiophene molecular chains can be wrapped around the surface of the carbon black particles, ultimately forming a composite conductive filler with conductive carbon black as the core and polythiophene as the coating layer. In semiconductor shielding materials, conductive carbon black particles in composite conductive fillers form continuous conductive pathways through physical contact. Polythiophene chains grow on the surface of conductive carbon black and entangle with each other through π-π conjugation, forming molecular-level conductive pathways. The conductive pathways of both interpenetrate and connect to form a double continuous conductive network, which enhances charge transport efficiency, reduces the volume resistivity of semiconductor shielding materials, and helps improve the conductivity of semiconductor shielding materials, thereby improving the shielding capability of pressure-resistant composite shielded cables.

[0017] 2. In this invention, the surface of halloysite nanotubes is modified to covalently graft aminopropyl-containing organic chains onto the surface of the halloysite nanotubes. Subsequently, the amino groups on the modified halloysite nanotube surface coordinate with calcium ions in an aqueous solution containing calcium chloride and urea, promoting heterogeneous nucleation and growth of calcium ions at the amino sites on the surface of the halloysite nanotubes. Then, the urea in the aqueous solution containing calcium chloride and urea undergoes a heating hydrolysis reaction to generate carbonate ions, which can react with the adsorbed calcium ions to generate calcium carbonate particles on the surface of the halloysite nanotubes, resulting in calcium carbonate-loaded halloysite nanotubes. This forms a composite dense reinforcing structure of "tubular halloysite nanotube framework" and "calcium carbonate particle reinforcing points," which can synergistically hinder the slippage and deformation of the matrix resin molecular chains, enhance the interfacial bonding force between the halloysite nanotubes and the matrix, and improve the tensile and compressive properties of the compression sheath material through stress transfer.

[0018] 3. In this invention, the sodium dodecyl sulfate and calcium carbonate-supported halloysite nanotubes undergo a heating and stirring reaction, causing the sulfate groups of sodium dodecyl sulfate to be stably adsorbed onto the surface of the calcium carbonate-supported halloysite nanotubes through electrostatic attraction. After the sodium dodecyl sulfate molecules are adsorbed onto the surface of the calcium carbonate-supported halloysite nanotubes, the dodecyl chains of sodium dodecyl sulfate spontaneously align outwards, forming an organic hydrophobic layer on the outer surface of the calcium carbonate-supported halloysite nanotubes. This reduces the surface energy of the calcium carbonate-supported halloysite nanotubes and decreases the tendency for aggregation between the particles, thereby improving the compatibility between the calcium carbonate-supported halloysite nanotubes and the resin matrix. The resulting anti-compression sleeve filler can more effectively transfer stress and reduce stress concentration through good dispersion and interfacial bonding, thereby improving the anti-compression performance of the anti-compression sleeve material. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1 A pressure-resistant composite shielded cable specifically includes the following steps: S1: Preparation of composite conductive filler S1.1: Add 12 parts by weight of conductive carbon black to 300 parts by weight of anhydrous chloroform and ultrasonically disperse at 23°C for 2 hours to uniformly disperse the conductive carbon black in chloroform and obtain a conductive carbon black dispersion. S1.2: Add 5.5 parts by weight of thiophene monomer to the conductive carbon black dispersion obtained in step S1.1, stir for 2 hours, then add 10 parts by weight of anhydrous ferric chloride to initiate the polymerization reaction, stir at 21°C for 10 hours, filter and collect the filter residue, wash the filter residue with anhydrous ethanol, dilute hydrochloric acid and deionized water in sequence until the washing liquid is colorless, and vacuum dry the washed filter residue at 50°C for 21 hours to obtain the composite conductive filler; S2: Preparation of semiconductive shielding material, Ethylene-vinyl acetate copolymer and low-density polyethylene are compounded at a mass ratio of 2.5:1 to obtain a matrix resin. 65 parts by weight of matrix resin, 14 parts by weight of composite conductive filler, 1.5 parts by weight of ethylene bis-stearamide, 0.85 parts by weight of antioxidant 1010, 2.1 parts by weight of triallyl isocyanurate and 1.4 parts by weight of microcrystalline wax are mixed, extruded and granulated to obtain a semiconductor shielding material. S3: Preparation of calcium carbonate-supported halloysite nanotubes S3.1: Place halloysite nanotubes in a vacuum drying oven and dry at 75°C for 4 hours. Take 12 parts by weight of the dried halloysite nanotubes and add them to 125 parts by weight of anhydrous ethanol. Disperse by ultrasonication for 12 minutes to form a halloysite nanotube suspension. S3.2: Under nitrogen protection, 7.5 parts by weight of 3-aminopropyltriethoxysilane were slowly added dropwise to the halloysite nanotube suspension obtained in step S3.1, with the dropping rate controlled at 0.75 mL / s. The mixture was stirred for 35 min, heated to 87 °C, and stirred for 3.5 h. After the reaction was completed, the mixture was cooled to room temperature, and the solid product A was collected by vacuum filtration. After washing and drying, the modified halloysite nanotubes were obtained. S3.3: Modified halloysite nanotubes were added to an aqueous solution containing calcium chloride and urea at a solid-liquid mass ratio of 2:55. The molar ratio of urea to calcium chloride in the aqueous solution containing calcium chloride and urea was 3:1. The solution was ultrasonically dispersed at room temperature for 30 min to obtain a dispersion. The dispersion was slowly heated to 63°C at a heating rate of 2°C / min to allow the urea to slowly hydrolyze and continuously generate carbonate ions. The pH of the solution system rose slowly and uniformly, promoting the deposition of calcium carbonate. After stirring continuously for 3 h, the solid product B was collected by vacuum filtration. After washing and drying, calcium carbonate-supported halloysite nanotubes were obtained. S4: Preparation of compression-resistant sheath packing S4.1: Dissolve sodium dodecyl sulfate in deionized water to prepare a sodium dodecyl sulfate solution with a mass fraction of 2.5%; S4.2: Calcium carbonate-supported halloysite nanotubes are mixed with sodium dodecyl sulfate solution from step S4.1 at a solid-liquid mass ratio of 1:18. After ultrasonic dispersion for 20 min, the mixture is stirred at 60 °C for 2 h, cooled to room temperature, and then filtered under reduced pressure, washed and dried to obtain the pressure-resistant sheath filler. S5: Preparation of pressure-resistant sheath material The compression sheath material is obtained by mixing, extruding, and granulating 70 parts by weight of chloroprene rubber, 18 parts by weight of compression sheath filler, 1.05 parts by weight of antioxidant 1010, 2.4 parts by weight of dioctyl phthalate and 3 parts by weight of tert-butyl perbenzoate. S6: Processing and preparation of pressure-resistant composite shielded cables S6.1: Cross-linked polyethylene is extruded onto the surface of a conductor, which is a tinned copper stranded wire made of 7 strands of tinned copper wire, forming an insulation layer to obtain a wire core. The thickness of the insulation layer is 0.5 mm. S6.2: Extruding semiconductor shielding material onto the surface of one strand of wire core to form a shielding inner layer with a thickness of 1.2 mm; S6.3: On the outside of the inner shielding layer, tin-plated copper wire is braided using a high-speed braiding machine at a braiding speed of 300 r / min and a braiding angle of 45° to form the outer shielding layer; S6.4: Extrude a layer of pressure-resistant sheath material onto the outer shielding layer to form a sheath layer with a thickness of 1.8mm, thus obtaining a pressure-resistant composite shielded cable.

[0021] Example 2 A pressure-resistant composite shielded cable specifically includes the following steps: S1: Preparation of composite conductive filler S1.1: Add 15 parts by weight of conductive carbon black to 400 parts by weight of anhydrous chloroform and ultrasonically disperse at 26°C for 3 hours to uniformly disperse the conductive carbon black in chloroform and obtain a conductive carbon black dispersion. S1.2: Add 7 parts by weight of thiophene monomer to the conductive carbon black dispersion obtained in step S1.1, stir for 3 hours, then add 12 parts by weight of anhydrous ferric chloride to initiate the polymerization reaction, stir at 24°C for 12 hours, filter and collect the filter residue, wash the filter residue with anhydrous ethanol, dilute hydrochloric acid and deionized water in sequence until the washing liquid is colorless, and vacuum dry the washed filter residue at 55°C for 24 hours to obtain the composite conductive filler; S2: Preparation of semiconductive shielding material, Ethylene-vinyl acetate copolymer and low-density polyethylene are compounded in a mass ratio of 3:1 to obtain a matrix resin. 70 parts by weight of the matrix resin, 18 parts by weight of the composite conductive filler, 2 parts by weight of ethylene bis-stearamide, 1.2 parts by weight of antioxidant 1010, 2.4 parts by weight of triallyl isocyanurate and 2.1 parts by weight of microcrystalline wax are mixed, extruded and granulated to obtain a semiconductor shielding material. S3: Preparation of calcium carbonate-supported halloysite nanotubes S3.1: Place halloysite nanotubes in a vacuum drying oven and dry at 80°C for 5 hours. Take 16 parts by weight of the dried halloysite nanotubes and add them to 150 parts by weight of anhydrous ethanol. Disperse by ultrasonication for 15 minutes to form a halloysite nanotube suspension. S3.2: Under nitrogen protection, 10 parts by weight of 3-aminopropyltriethoxysilane were slowly added dropwise to the halloysite nanotube suspension obtained in step S3.1. The dropping rate was controlled at 1 mL / s. The mixture was stirred for 40 min, heated to 94 °C, and stirred for 5 h. After the reaction was completed, the mixture was cooled to room temperature, and the solid product A was collected by vacuum filtration. After washing and drying, the modified halloysite nanotubes were obtained. S3.3: Modified halloysite nanotubes were added to an aqueous solution containing calcium chloride and urea at a solid-liquid mass ratio of 3:80. The molar ratio of urea to calcium chloride in the aqueous solution containing calcium chloride and urea was 3:1. The solution was ultrasonically dispersed at room temperature for 40 min to obtain a dispersion. The dispersion was slowly heated to 66℃ at a heating rate of 3℃ / min to allow the urea to slowly hydrolyze and continuously generate carbonate ions. The pH of the solution system rose slowly and uniformly, promoting the deposition of calcium carbonate. After stirring continuously for 4 h, the solid product B was collected by vacuum filtration. After washing and drying, calcium carbonate-supported halloysite nanotubes were obtained. S4: Preparation of compression-resistant sheath packing S4.1: Dissolve sodium dodecyl sulfate in deionized water to prepare a 4% sodium dodecyl sulfate solution; S4.2: Calcium carbonate-supported halloysite nanotubes are mixed with sodium dodecyl sulfate solution from step S4.1 at a solid-liquid mass ratio of 1:20. After ultrasonic dispersion for 30 min, the mixture is stirred at 70 °C for 3 h, cooled to room temperature, and then filtered under reduced pressure, washed and dried to obtain the pressure-resistant sheath filler. S5: Preparation of pressure-resistant sheath material The compression sheath material is obtained by mixing, extruding, and granulating 80 parts by weight of chloroprene rubber, 24 parts by weight of compression sheath filler, 1.6 parts by weight of antioxidant 1010, 4 parts by weight of dioctyl phthalate and 5 parts by weight of tert-butyl perbenzoate. S6: Processing and preparation of pressure-resistant composite shielded cables S6.1: Cross-linked polyethylene is extruded onto the surface of a conductor, which is a tinned copper stranded wire made of 7 strands of tinned copper wire, forming an insulation layer to obtain a wire core. The thickness of the insulation layer is 0.5 mm. S6.2: Extruding semiconductor shielding material onto the surface of one strand of wire core to form a shielding inner layer with a thickness of 1.2 mm; S6.3: On the outside of the inner shielding layer, tin-plated copper wire is braided using a high-speed braiding machine at a braiding speed of 300 r / min and a braiding angle of 45° to form the outer shielding layer; S6.4: Extrude a layer of pressure-resistant sheath material onto the outer shielding layer to form a sheath layer with a thickness of 1.8mm, thus obtaining a pressure-resistant composite shielded cable.

[0022] Example 3 A pressure-resistant composite shielded cable specifically includes the following steps: S1: Preparation of composite conductive filler S1.1: Add 9 parts by weight of conductive carbon black to 200 parts by weight of anhydrous chloroform and ultrasonically disperse at 20°C for 1 hour to uniformly disperse the conductive carbon black in chloroform and obtain a conductive carbon black dispersion. S1.2: Add 4 parts by weight of thiophene monomer to the conductive carbon black dispersion obtained in step S1.1, stir for 1 hour, then add 8 parts by weight of anhydrous ferric chloride to initiate the polymerization reaction, stir at 18°C ​​for 8 hours, filter to collect the filter residue, wash the filter residue with anhydrous ethanol, dilute hydrochloric acid and deionized water in sequence until the washing liquid is colorless, and vacuum dry the washed filter residue at 45°C for 18 hours to obtain the composite conductive filler; S2: Preparation of semiconductive shielding material, Ethylene-vinyl acetate copolymer and low-density polyethylene are compounded at a mass ratio of 2:1 to obtain a matrix resin. 60 parts by weight of the matrix resin, 10 parts by weight of the composite conductive filler, 1 part by weight of ethylene bis-stearamide, 0.5 parts by weight of antioxidant 1010, 1.8 parts by weight of triallyl isocyanurate and 0.3 parts by weight of microcrystalline wax are mixed, extruded and granulated to obtain a semiconductor shielding material. S3: Preparation of calcium carbonate-supported halloysite nanotubes S3.1: Place halloysite nanotubes in a vacuum drying oven and dry at 70°C for 3 hours. Take 8 parts by weight of the dried halloysite nanotubes and add them to 100 parts by weight of anhydrous ethanol. Disperse by ultrasonication for 10 minutes to form a halloysite nanotube suspension. S3.2: Under nitrogen protection, 5 parts by weight of 3-aminopropyltriethoxysilane were slowly added dropwise to the halloysite nanotube suspension obtained in step S3.1. The dropping rate was controlled at 0.5 mL / s. The mixture was stirred for 30 min, heated to 80 °C, and stirred for 2 h. After the reaction was completed, the mixture was cooled to room temperature, and the solid product A was collected by vacuum filtration. After washing and drying, the modified halloysite nanotubes were obtained. S3.3: Modified halloysite nanotubes were added to an aqueous solution containing calcium chloride and urea at a solid-liquid mass ratio of 1:30. The molar ratio of urea to calcium chloride in the aqueous solution containing calcium chloride and urea was 3:1. The solution was ultrasonically dispersed at room temperature for 20 min to obtain a dispersion. The dispersion was slowly heated to 60°C at a heating rate of 1°C / min to allow the urea to slowly hydrolyze and continuously generate carbonate ions. The pH of the solution system rose slowly and uniformly, promoting the deposition of calcium carbonate. After stirring continuously for 2 h, the solid product B was collected by vacuum filtration. After washing and drying, calcium carbonate-supported halloysite nanotubes were obtained. S4: Preparation of compression-resistant sheath packing S4.1: Dissolve sodium dodecyl sulfate in deionized water to prepare a 1% sodium dodecyl sulfate solution; S4.2: Calcium carbonate-supported halloysite nanotubes are mixed with sodium dodecyl sulfate solution from step S4.1 at a solid-liquid mass ratio of 1:16. After ultrasonic dispersion for 10 min, the mixture is stirred at 50 °C for 1 h, cooled to room temperature, and then filtered under reduced pressure, washed and dried to obtain the pressure-resistant sheath filler. S5: Preparation of pressure-resistant sheath material The compression sheath material is obtained by mixing, extruding, and granulating 60 parts by weight of chloroprene rubber, 12 parts by weight of compression sheath filler, 0.5 parts by weight of antioxidant 1010, 0.8 parts by weight of dioctyl phthalate and 1 part by weight of tert-butyl perbenzoate. S6: Processing and preparation of pressure-resistant composite shielded cables S6.1: Cross-linked polyethylene is extruded onto the surface of a conductor, which is a tinned copper stranded wire made of 7 strands of tinned copper wire, forming an insulation layer to obtain a wire core. The thickness of the insulation layer is 0.5 mm. S6.2: Extruding semiconductor shielding material onto the surface of one strand of wire core to form a shielding inner layer with a thickness of 1.2 mm; S6.3: On the outside of the inner shielding layer, tin-plated copper wire is braided using a high-speed braiding machine at a braiding speed of 300 r / min and a braiding angle of 45° to form the outer shielding layer; S6.4: Extrude a layer of pressure-resistant sheath material onto the outer shielding layer to form a sheath layer with a thickness of 1.8mm, thus obtaining a pressure-resistant composite shielded cable.

[0023] Comparative Example 1 Compared with Example 1, the difference of Comparative Example 1 is that the composite conductive filler in step S2 is replaced with an equal part by weight of conductive carbon black, while the other steps remain unchanged, and a semiconductor shielding material is prepared, which is referred to as Comparative Example 1.

[0024] Comparative Example 2 Compared with Example 1, the difference of Comparative Example 2 is that the composite conductive filler in step S2 is replaced with an equal part by weight of polythiophene, while the other steps remain unchanged, and a semiconductor shielding material is prepared, which is referred to as Comparative Example 2.

[0025] Comparative Example 3 Compared with Example 1, Comparative Example 3 differs in that step S1 is removed. 300 parts by weight of anhydrous chloroform and 10 parts by weight of anhydrous ferric chloride are added to a reaction flask and ultrasonically dispersed for 30 min. Subsequently, 5.5 parts by weight of thiophene monomer are added to the reaction flask and stirred at 21°C for 10 h. After the reaction is completed, the residue is filtered and washed sequentially with anhydrous ethanol, dilute hydrochloric acid, and deionized water until the washing liquid is colorless. The washed residue is then vacuum dried at 50°C for 21 h to obtain polythiophene. The obtained polythiophene is mixed evenly with 12 parts by weight of conductive carbon black to obtain a mixed conductive filler. The composite conductive filler in step S2 is replaced with an equal part by weight of the mixed conductive filler, while the other steps remain unchanged, to prepare a semiconductor shielding material, which is designated as Comparative Example 3.

[0026] The semiconductor shielding materials obtained in Examples 1-3 and Comparative Examples 1-3 were pressed into 5 test samples with a length and width of 10cm and a thickness of 1mm. The performance of the test samples was tested and the average value was taken. The results are shown in Table 1.

[0027] Table 1:

[0028] As shown in Table 1, the volume resistivity of the test samples in Examples 1-3 was significantly lower than that of Comparative Examples 1-3 at both room temperature (23℃) and high temperature (90℃). Compared with Comparative Example 1, which used only conductive carbon black as a filler, and Comparative Example 2, which used only polythiophene as a filler, the semiconductor shielding materials prepared in Examples 1-3 all exhibited superior conductivity. This indicates that although both conductive carbon black and polythiophene have a certain degree of conductivity, the conductive pathways formed between particles are relatively simple, resulting in low charge transport efficiency and thus high volume resistivity. Comparative Example 3 used a material obtained by mechanically mixing conductive carbon black and polythiophene as a filler. Although the volume resistivity was improved compared to Comparative Examples 1-2, it was still inferior to the semiconductor shielding materials prepared in Examples 1-3. This indicates that physical mixing can only achieve simple coexistence of conductive carbon black and polythiophene. The lack of strong interaction between the two leads to discontinuous conductive pathways, increased charge transport resistance, and limited ability to improve the conductivity of semiconductor shielding materials.

[0029] Comparative Example 4 Compared with Example 1, the difference of Comparative Example 4 is that the pressure-resistant sheath filler in step S5 is replaced with an equal weight of calcium carbonate-supported halloysite nanotubes obtained in step S3.3, while the other steps remain unchanged, and the pressure-resistant sheath material is prepared, which is referred to as Comparative Example 4.

[0030] Comparative Example 5 Compared with Example 1, Comparative Example 5 differs in that step S3 is removed, and the calcium carbonate-supported halloysite nanotubes in step S4.2 are replaced with halloysite nanotubes. The halloysite nanotubes are mixed with the sodium dodecyl sulfate solution in step S4.1 at a solid-liquid mass ratio of 1:18, ultrasonically dispersed for 20 min, stirred at 60°C for 2 h, cooled to room temperature, and then subjected to vacuum filtration, washing, and drying to obtain the pressure-resistant sheath filler. The remaining steps remain unchanged, and the pressure-resistant sheath material is prepared and is referred to as Comparative Example 5.

[0031] The compression-resistant sheath materials obtained in Examples 1-3 and Comparative Examples 4-5 were pressed into 5 test specimens, each with a length and width of 10cm and a thickness of 1mm. The performance of the test specimens was tested, and the average value was taken. The results are shown in Table 2.

[0032] Table 2:

[0033] As shown in Table 2, the tensile strengths of the test specimens in Examples 1-3 were 27.95 MPa, 25.22 MPa, and 23.47 MPa, respectively; the elongation at break were 348.38%, 346.05%, and 340.83%, respectively; and the notched impact strength was 79.3 kJ / m, respectively. 2 77.7kJ / m 2 74.1 kJ / m2 The tensile strength, elongation at break, and notched impact strength of the material are significantly superior to those of Comparative Examples 4-5, demonstrating excellent tensile and compressive properties. Comparative Example 4, in preparing the compressive sheath material, did not use sodium dodecyl sulfate for surface treatment of the calcium carbonate-supported halloysite nanotubes; instead, it directly used the calcium carbonate-supported halloysite nanotubes as fillers. The tensile strength, elongation at break, and notched impact strength were 19.36 MPa, 322.21%, and 63.8 kJ / m², respectively. 2 The tensile and compressive strengths of the calcium carbonate-supported halloysite nanotubes were all lower than those of Examples 1-3, indicating that surface treatment of calcium carbonate-supported halloysite nanotubes with sodium dodecyl sulfate can improve the dispersion and interfacial bonding of calcium carbonate-supported halloysite nanotubes in the compression sheath material, enhance stress transfer efficiency, and thus improve the tensile and compressive strength of the compression sheath material. In Comparative Example 5, step S3 was removed, and the calcium carbonate-supported halloysite nanotubes in step S4.2 were replaced with halloysite nanotubes. The composite dense reinforcement structure of "tubular halloysite nanotube skeleton" and "calcium carbonate particle reinforcing points" was not formed. The tensile strength, elongation at break, and notched impact strength were only 16.18 MPa, 307.74%, and 55.3 kJ / m, respectively. 2 This indicates that without the reinforcing effect of calcium carbonate particles, relying solely on halloysite nanotubes cannot form a dense reinforcing system, resulting in weak stress transmission capacity and significantly lower mechanical strength compared to Examples 1-3.

[0034] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims. Parts not described in detail in this specification are prior art known to those skilled in the art.

Claims

1. A pressure-resistant composite shielded cable, comprising the following parts from the inside out: The core, inner shielding layer, outer shielding layer, and sheath layer are as follows: The wire core includes a conductor and an insulating layer disposed on the outside of the conductor; the conductor is tin-plated copper stranded wire. The outer shielding layer is woven from tin-plated copper wire; Its characteristic is that the raw material of the inner shielding layer is a semi-conductive shielding material, and the raw materials for preparing the semi-conductive shielding material include: 60-70 parts by weight of matrix resin, 10-18 parts by weight of composite conductive filler, 1-2 parts by weight of dispersant, 0.5-1.2 parts by weight of antioxidant, 1.8-2.4 parts by weight of crosslinking agent and 0.3-2.1 parts by weight of lubricant; The raw materials for preparing the composite conductive filler include: 9-15 parts by weight of conductive carbon black, 200-400 parts by weight of anhydrous chloroform, 4-7 parts by weight of thiophene monomer and 8-12 parts by weight of anhydrous ferric chloride. The raw material for the sheath layer is a pressure-resistant sheath material, and the raw materials for preparing the pressure-resistant sheath material include: 60-80 parts by weight of chloroprene rubber, 12-24 parts by weight of compression sheath filler, 0.5-1.6 parts by weight of antioxidant, 0.8-4 parts by weight of plasticizer and 1-5 parts by weight of vulcanizing agent; The raw materials for the pressure-resistant sheath packing include: Halloysite nanotubes supported on calcium carbonate and sodium dodecyl sulfate solution were prepared. The solid-liquid mass ratio of the halloysite nanotubes supported on calcium carbonate to the sodium dodecyl sulfate solution was 1:(16-20). The sodium dodecyl sulfate solution had a sodium dodecyl sulfate mass fraction of 1-4%. The halloysite nanotubes supported on calcium carbonate were halloysite nanotubes with calcium carbonate deposited on their surface.

2. The pressure-resistant composite shielded cable according to claim 1, characterized in that, The insulation layer is made of one of cross-linked polyethylene, ethylene propylene rubber, or thermoplastic vulcanized rubber, and the wire core has at least one strand.

3. The pressure-resistant composite shielded cable according to claim 1, characterized in that, The matrix resin is a compound of ethylene-vinyl acetate copolymer and low-density polyethylene in a mass ratio of (2-3):

1.

4. The pressure-resistant composite shielded cable according to claim 1, characterized in that, The preparation steps include the following: S1: Preparation of composite conductive filler: Conductive carbon black is dispersed in anhydrous chloroform to obtain conductive carbon black dispersion. Thiophene monomer and anhydrous ferric chloride are added to the conductive carbon black dispersion, and the mixture is stirred to react. After the reaction is completed, the filter residue is collected by filtration. The filter residue is washed and dried to obtain composite conductive filler. S2: Preparation of semiconductive shielding material: Mixing, extruding and granulating the raw materials required for preparing semiconductive shielding material to obtain semiconductor shielding material; S3: Preparation of halloysite nanotubes supported on calcium carbonate: Halloysite nanotubes were dispersed in anhydrous ethanol to form a halloysite nanotube suspension. Under nitrogen protection, 3-aminopropyltriethoxysilane was slowly added dropwise to the halloysite nanotube suspension and stirred to obtain modified halloysite nanotubes. The modified halloysite nanotubes were added to an aqueous solution containing calcium chloride and urea and slowly heated to allow the urea to slowly hydrolyze, continuously generating carbonate ions, which promoted the deposition of calcium carbonate. Subsequently, the solid product was collected by vacuum filtration, washed and dried to obtain calcium carbonate supported halloysite nanotubes. S4: Preparation of the compression-resistant sheath filler: Sodium dodecyl sulfate was dissolved in deionized water to prepare a sodium dodecyl sulfate solution. Calcium carbonate-supported halloysite nanotubes were mixed with the sodium dodecyl sulfate solution and heated and stirred for a period of time. Subsequently, the mixture was cooled to room temperature and then subjected to vacuum filtration, washing, and drying to obtain the compression-resistant sheath filler. S5: Preparation of the pressure-resistant sheath material: The raw materials required for the preparation of the pressure-resistant sheath material are mixed, extruded, and granulated to obtain the pressure-resistant sheath material; S6: The processing and preparation of the pressure-resistant composite shielded cable involves extruding semiconductor shielding material onto the surface of the core to form an inner shielding layer. On the outside of the inner shielding layer, tin-plated copper wire is braided using a high-speed braiding machine to form an outer shielding layer. Finally, a layer of pressure-resistant sheathing material is extruded onto the outer shielding layer to form a sheathing layer, thus obtaining the pressure-resistant composite shielded cable.

5. The pressure-resistant composite shielded cable according to claim 4, characterized in that, Step S1, the preparation of the composite conductive filler, specifically includes the following steps: S1.1: Add 9-15 parts by weight of conductive carbon black to 200-400 parts by weight of anhydrous chloroform and ultrasonically disperse at 20-26°C for 1-3 hours to obtain a conductive carbon black dispersion. S1.2: Add 4-7 parts by weight of thiophene monomer to the conductive carbon black dispersion obtained in step S1.1, stir for 1-3 hours, then add 8-12 parts by weight of anhydrous ferric chloride, stir at 18-24°C for 8-12 hours, filter after the reaction is complete, and wash and dry the filter residue to obtain the composite conductive filler.

6. The pressure-resistant composite shielded cable according to claim 4, characterized in that, Step S3, the preparation of calcium carbonate-supported halloysite nanotubes, specifically includes the following steps: S3.1: Place halloysite nanotubes in a vacuum drying oven and dry at 70-80℃ for 3-5 hours. Take 8-16 parts by weight of the dried halloysite nanotubes and add them to 100-150 parts by weight of anhydrous ethanol. Disperse by ultrasonication for 10-15 minutes to form a halloysite nanotube suspension. S3.2: Under nitrogen protection, 5-10 parts by weight of 3-aminopropyltriethoxysilane were slowly added dropwise to the halloysite nanotube suspension obtained in step S3.1, with the dropping rate controlled at 0.5-1 mL / s. The mixture was stirred for 30-40 min, heated to 80-94 °C, and stirred for 2-5 h. After the reaction was completed, the mixture was cooled to room temperature, and the solid product A was collected by vacuum filtration. After washing and drying, the modified halloysite nanotubes were obtained. S3.3: Take modified halloysite nanotubes and add them to an aqueous solution containing calcium chloride and urea at a solid-liquid mass ratio of (1-3):(30-80). Disperse the solution by ultrasonication at room temperature for 20-40 min to obtain a dispersion. Heat the dispersion slowly to 60-66℃ at a heating rate of 1-3℃ / min to allow the urea to hydrolyze slowly. After stirring continuously for 2-4 h, collect the solid product B by vacuum filtration. After washing and drying, obtain calcium carbonate supported halloysite nanotubes.

7. The pressure-resistant composite shielded cable according to claim 6, characterized in that, In an aqueous solution containing calcium chloride and urea, the molar ratio of urea to calcium chloride is 3:

1.

8. The pressure-resistant composite shielded cable according to claim 4, characterized in that, Step S4, the preparation of the compression sheath packing, specifically includes the following steps: S4.1: Dissolve sodium dodecyl sulfate in deionized water to prepare a sodium dodecyl sulfate solution with a mass fraction of 1-4%; S4.2: Mix calcium carbonate-supported halloysite nanotubes with sodium dodecyl sulfate solution from step S4.1 at a solid-liquid mass ratio of 1:(16-20), ultrasonically disperse for 10-30 min, stir at 50-70℃ for 1-3 h, cool to room temperature, and obtain pressure-resistant sheath filler by vacuum filtration, washing and drying.

9. The pressure-resistant composite shielded cable according to claim 1, characterized in that, The dispersant is at least one of polyethylene wax and ethylene bis-stearamide; the antioxidant is at least one of antioxidant 1010, antioxidant 1076, antioxidant TPP, and antioxidant 168; the crosslinking agent is triallyl isocyanurate or dicumyl peroxide; and the lubricant is at least one of microcrystalline wax, silicone oil, and zinc stearate.

10. A pressure-resistant composite shielded cable according to claim 9, characterized in that, The plasticizer is at least one of dioctyl phthalate, dibutyl phthalate, and diisononyl phthalate; the vulcanizing agent is at least one of tert-butyl perbenzoate, dicumyl peroxide, and tert-butyl cumyl peroxide.

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